<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script type="text/javascript" src="../jquery/jquery-3.5.1.js"></script>
<script type="text/javascript">
  $(function (){
    alert($("input[name!='newsletter']").length)
  })
</script>
<form>
<input type="button" name="newsletter" value="hot fuzz">
<input type="button" name="newsletter" value="cold fusion">
<input type="button"  value="evil plans">
</form>
</body>
</html>